Technical Tips

May 2009

Are Deep Face Clubheads A Thing Of The Past?-- by Jeff Summitt

Modern design has given the once top dog more competition

I have had a few people of late who have asked me “Why are driver heads are so shallow, what happened to the deep face clubs from a few years ago?” There are several reasons why with perhaps the biggest reason being manufacturers are attempting to enhance performance. While a deep face (59mm+ for drivers) club may provide added room for error and instill more confidence at address, there a few things to understand.

Center of gravity follows geometry
The deeper the face the higher the center of gravity (CG) of the club will be. This is due to the fact the CG follows the geometry of the head. Most clubs today are nearly all the maximum 460cc. If a club face is deep (or tall), then the club cannot be as broad from face to back otherwise the volume will exceed the limits set forth by the USGA. And no manufacturer (or consumer) wants the club narrower from heel-to-toe to make up for that difference in volume. If a head is narrow from front-to-back (breadth) then the CG will be more forward or closer to the face as well. Why? If the area of the club face is bigger then more material is required. This additional weight pulls the CG toward the face. We will see what effect this has a little later. If the club is not as broad from front-to-back, the moment of inertia (MOI) will not be as high, at least as how golf manufacturers measure the MOI of their heads.

Launch Conditions
Let’s recap; the CG is both higher and forward with a deeper faced clubhead. This will create totally different launch conditions than the modern driver which is shallow and broad. Given the same loft, the ball flight with a deeper faced clubhead will be lower therefore the person might have to opt for a slightly higher loft. It was only a few years ago when launch monitor became widely available. Club fitters were telling people to use more loft. Is it any coincidence the driver heads were deeper face back then? Today you don’t hear that same suggestion with as much frequency. If the CG location is forward it will create a slightly higher spin rate; this is why the is being broader to shift the CG back to reduce spin. So that equates to low launch / high spin

Additional spin can be good for some golfers. But if additional loft needed to achieve the optimum launch angle and you now have created even more spin (due to the higher loft) and potentially a distance killer for golfers with higher swing speeds (excessive spin). If one can get the correct launch angle using a lower lofted driver, they can potentially obtain more distance as a higher initial ball speed will be a result. This is why so many heads on the market today are shallower and/or internally weighted. Choosing the right shaft can assist in promoting a higher launch angle, even if the shaft is more flexible. After all, the massive driver heads are much more forgiving today to compensate for directional problems.

For fairways and hybrids, creating a deep faced design makes it more difficult to hit off of the ground (as they are primarily designed) because you don’t have the assistance of a tee as you do with the driver. One thing to remember, even the modern shallower drivers are deeper face compared to clubs made not that long ago. The average driver face height today (53-57mm) is about the same as when 400cc drivers first appeared on the market. The actual face height is really only quarter-inch (6mm) or less than those really deep faced drivers. One more reason why golfers may feel the heads may not appear as deep since the modern clubhead is broader from front-to-back when in fact they really are. Lastly, the crowns are flatter on modern drivers reducing the head’s height giving the added perception that the actual face height may be shallower.

As you can see there is a number of reasons why deeper face clubs are not as common today. But if you hit a high ball with less spin than you need, a deeper faced club with reduced breadth might be for you. Otherwise understand and take advantage of the current trend in modern driver design.